1. Field of the Invention
This invention pertains to an optical fiber connector for precisely positioning and aligning a pair of optical fibers.
2. Description of the Prior Art
The increased use of optical fibers in the telecommunications and signal transmission industries has lead to the need to develop connectors for optically connecting fiber pairs. Examples of such connectors are shown in U.S. Pat. No. 4,684,205, U.S. Pat. No. 4,422,716 and U.S. Pat. No. 4,850,670.
Notwithstanding prior art developments in optical fiber connectors, there is a continuing need for improved connector designs. Connectors must be compact, of minimum cost to manufacture, and should insure good optical coupling between connected fibers.
One of the problems encountered in the design of optical fiber connectors is the need to retain proper face-to-face contact between the opposing fibers. It is desirable to have the opposing fibers of two joined connectors to be in physical contact with the fibers exerting a predetermined minimum force against each other. This force must be sufficient to insure that the cores of the fibers are sufficiently close over a required operating temperature range (for example, -50.degree. C. to 85.degree. C.).
One common way of holding a fiber in a connector is through the use of a so-called crimp-style connector. The aforementioned U.S. Pat. No. 4,684,205 shows a crimp-style connector where a fiber is held in a clamp (item 17 in U.S. Pat. No. 4,684,205) with a point of contact spaced away from the end of the fiber. The fiber then passes through a ferrule (item 25 in the aforementioned U.S. Pat. No. 4,684,205) and may float freely within the ferrule. In such a configuration, when the connector is heated through increases in ambient temperature, the ferrule (commonly, made from glass or ceramic) will expand at a rate greater than the rate of expansion of the fiber (commonly, made from fused silica). As a result, the contacting force between the two opposing fibers may decrease below a desired minimum force since the ferrules may expand faster than the fibers. As a result, the ferrules will bear the forces intended to be experienced by the fibers.
In addition to maintaining a desired minimum contact force between the opposing fibers, it is also desirable that a connector design will address other problems encountered in the art. These include providing sleeves for aligning the ferrules in a manner which results in uniform pressure distribution on the ferrule. And the sleeves should accommodate a tendency of fibers to offset from optical alignment as the fibers approach one another within the sleeve. In addition, it is desirable that an improved connector design will address the problems associated with chipping of fibers.
It is an object of the present invention to address each of the above issues as well as others associated with optical fiber connector design.